co·lum·bite 
(kə-lŭmbīt′)
(kə-lŭmbīt′)n.
A black, red-brown, or colorless mineral, essentially (Fe, Mn)(Nb, Ta)2O6, the principal ore of niobium.
[COLUMB(IUM) + -ITE1.]
- unprovoked
- unpublishable
- unputdownable
- unqualified
- unqualifiedly
- unquenchable
- unquenchably
- unquestionability
- unquestionable
- unquestionableness
- unquestionably
- unquestioned
- unquestioning
- unquestioningly
- unquiet
- unquietly
- unquietness
- unquote
- unravel
- unreachability
- unreachable
- unreachably
- unread
- unreadability
- unreadable